Handling of LUA_PATH/LUA_CPATH moved from package library to stand

alone interpreter (so that 'lua.c' concentrates all handling of
environment variables)

lua.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lua.c,v 1.225 2015/03/30 15:42:59 roberto Exp roberto $
+** $Id: lua.c,v 1.226 2015/08/14 19:11:20 roberto Exp roberto $
 ** Lua stand-alone interpreter
 ** See Copyright Notice in lua.h
 */
@@ -55,6 +55,8 @@
 #elif defined(LUA_USE_WINDOWS)	/* }{ */
 
 #include <io.h>
+#include <windows.h>
+
 #define lua_stdin_is_tty()	_isatty(_fileno(stdin))
 
 #else				/* }{ */
@@ -529,6 +531,91 @@ static int runargs (lua_State *L, char **argv, int n) {
 }
 
 
+
+/*
+** {==================================================================
+** Set Paths
+** ===================================================================
+*/
+
+/*
+** LUA_PATH_VAR and LUA_CPATH_VAR are the names of the environment
+** variables that Lua check to set its paths.
+*/
+#if !defined(LUA_PATH_VAR)
+#define LUA_PATH_VAR    "LUA_PATH"
+#endif
+
+#if !defined(LUA_CPATH_VAR)
+#define LUA_CPATH_VAR   "LUA_CPATH"
+#endif
+
+#define LUA_PATHSUFFIX          "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR
+
+#define LUA_PATHVARVERSION              LUA_PATH_VAR LUA_PATHSUFFIX
+#define LUA_CPATHVARVERSION             LUA_CPATH_VAR LUA_PATHSUFFIX
+
+
+#define AUXMARK         "\1"	/* auxiliary mark */
+
+
+#if defined(LUA_USE_WINDOWS)
+
+
+/*
+** Replace in the path (on the top of the stack) any occurrence
+** of LUA_EXEC_DIR with the executable's path.
+*/
+static void setprogdir (lua_State *L) {
+  char buff[MAX_PATH + 1];
+  char *lb;
+  DWORD nsize = sizeof(buff)/sizeof(char);
+  DWORD n = GetModuleFileNameA(NULL, buff, nsize);  /* get exec. name */
+  if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
+    luaL_error(L, "unable to get ModuleFileName");
+  else {
+    *lb = '\0';  /* cut name on the last '\\' to get the path */
+    luaL_gsub(L, lua_tostring(L, -1), LUA_EXEC_DIR, buff);
+    lua_remove(L, -2);  /* remove original string */
+  }
+}
+
+#else
+
+#define setprogdir(L)           ((void)0)
+
+#endif
+
+/*
+** Change a path according to corresponding environment variables
+*/
+static void chgpath (lua_State *L, const char *fieldname,
+                                   const char *envname1,
+                                   const char *envname2,
+                                   int noenv) {
+  const char *path = getenv(envname1);
+  lua_getglobal(L, LUA_LOADLIBNAME);  /* get 'package' table */
+  lua_getfield(L, -1, fieldname);  /* get original path */
+  if (path == NULL)  /* no environment variable? */
+    path = getenv(envname2);  /* try alternative name */
+  if (path == NULL || noenv)  /* no environment variable? */
+    lua_pushvalue(L, -1);  /* use original value */
+  else {
+    const char *def = lua_tostring(L, -1);  /* default path */
+    /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
+    path = luaL_gsub(L, path, LUA_PATH_SEP LUA_PATH_SEP,
+                              LUA_PATH_SEP AUXMARK LUA_PATH_SEP);
+    luaL_gsub(L, path, AUXMARK, def);
+    lua_remove(L, -2); /* remove result from 1st 'gsub' */
+  }
+  setprogdir(L);
+  lua_setfield(L, -3, fieldname);  /* set path value */
+  lua_pop(L, 2);  /* pop 'package' table and original path  */
+}
+
+/* }================================================================== */
+
+
 static int handle_luainit (lua_State *L) {
   const char *name = "=" LUA_INITVARVERSION;
   const char *init = getenv(name + 1);
@@ -561,11 +648,10 @@ static int pmain (lua_State *L) {
   }
   if (args & has_v)  /* option '-v'? */
     print_version();
-  if (args & has_E) {  /* option '-E'? */
-    lua_pushboolean(L, 1);  /* signal for libraries to ignore env. vars. */
-    lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
-  }
   luaL_openlibs(L);  /* open standard libraries */
+  /* change paths according to env variables */
+  chgpath(L, "path", LUA_PATHVARVERSION, LUA_PATH_VAR, (args & has_E));
+  chgpath(L, "cpath", LUA_CPATHVARVERSION, LUA_CPATH_VAR, (args & has_E));
   createargtable(L, argv, argc, script);  /* create table 'arg' */
   if (!(args & has_E)) {  /* no option '-E'? */
     if (handle_luainit(L) != LUA_OK)  /* run LUA_INIT */